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Biomedical subjects

T Köhler

Publications and source records attributed to T Köhler.

At least 109 records · Page 6Linked to original sources
PubMed1990

Daily stress as a trigger of migraine attacks: results of thirteen single-subject studies.

A 6-month longitudinal study examined whether migraine attacks were preceded by or occurred on stressful days. Every evening 13 patients filled out a questionnaire assessing daily stress. Analyses on single-subject level tested whether attacks occurred more often than expected by chance 3, 2, or 1 day after or on day when stress scores were in the upper third of the subject's distribution. Increased stress was generally not found for Days 2 and 3 before an attack, but often for Day 1 and on the migraine day itself. The latter findings were also significant on a group level.

Adaptation, Psychological↗
PubMed1990

Growth-phase-dependent expression of the Pseudomonas putida TOL plasmid pWW0 catabolic genes.

Pseudomonas putida TOL plasmid pWW0 catabolic genes are clustered into two operons. The first, the upper operon, is controlled by the xylR regulatory gene, whereas the second, the meta operon, is controlled by the xylS regulatory gene. The xylS gene itself is subjected to control by xylR. In this study, we show that the TOL catabolic operons were poorly induced in cells growing at the early-exponential-growth phase but strongly induced in cells at late-exponential-growth phase. We constructed fusions of four TOL promoters, Pm (the promoter of the meta operon), Pu (the promoter of the upper operon), Ps (the promoter of the xylS regulatory gene), and Pr (the promoter of the xylR regulatory gene) with lacZ and examined, in Escherichia coli and P. putida, the expression of these promoters in relation to the growth phase. Expression from Pm, Pu, Ps, and Pr was almost constant if the host cells did not carry either xylS or xylR. Similarly, expression of Pm and Pu in P. putida in the absence of XylS and XylR was constant during the growth of the cells. XylS-dependent transcription of Pm and XylR-dependent transcription of Ps and Pu, in contrast, varied with the growth phase. This observation suggested that the interaction of XylS and XylR with target promoters or with RNA polymerases was influenced by the growth phase. The nature of the signal which triggers the growth-phase-dependent regulation was not clear. A change in the oxygen partial pressure was not responsible for the regulation. E. coli mutants defective in relA, crp, and cya exhibited growth-phase-dependent expression of the TOL catabolic genes, indicating that cyclic AMP and relA-dependent synthesis of ppGpp are not involved in this phenomenon.

Cloning, Molecular↗
PubMed1990

[The number of active sweat glands (PSI, palmar sweat index) in stress caused by blood donation].

The number of active sweat glands (PSI), heart rate, systolic (SBP) and diastolic blood pressure (DBP) were assessed every 2 minutes in 109 male blood donors. Three measurements were taken at the beginning (adaptation phase), three later but before blood donation (baseline), one during the venous puncture (phase 3), three thereafter but still during donation (phase 4), and four after removal of the cannula (phase 5). Analysis of variance yielded significant differences between phases; PSI and SBP behaved similarly, decreasing from adaptation to baseline, rising during puncture, and decreasing again thereafter. Mean within-subject correlations between variables were significantly above 0. Between-subjects correlations were significantly negative for PSI and DBP. This is best explained by the influence of age on both variables. Correlations of PSI values as determined by three raters had a mean of 0.90. The study shows that the PSI is a very sensitive indicator of stress that is easily accessible also in field studies.

Adult↗
PubMed1990

[Histological findings of the small intestinal mucosa in rotavirus infections in infants and young children].

In a prospective study we performed small intestinal mucosal biopsies in 40 children with acute rotavirus diarrhoea. Biopsies were taken from these children between the 2nd to 10th day of acute phase. The children were at an age of less than 18 month. 95% of the patients had normal histological findings of the small intestinal mucosa. Only 2 children (5%) had well defined injuries of intestinal mucosa. Correlations were not found between clinical findings, morphological results and therapy. In one child with gastroenteritis and meningitis rotaviruses were found in cerebrospinal fluid. In 31.25% of all children rotavirus infection was acquired by a nosocomial infection. The treatment of rotavirus infection is symptomatic. Usually intestinal mucosal biopsy as a routine diagnostic method isn't recommended and it should be used only in intractable courses.

Biopsy↗
PubMed1989

Involvement of Pseudomonas putida RpoN sigma factor in regulation of various metabolic functions.

The RpoN protein was originally identified in Escherichia coli as a sigma (sigma) factor essential for the expression of nitrogen regulons. In the present study we cloned the Pseudomonas putida rpoN gene and identified its gene product as a protein with an apparent molecular weight of 78,000. A mutant rpoN gene was constructed by in vitro insertion mutagenesis with a kanamycin cassette. A P. putida rpoN mutant was then isolated by replacement of the intact chromosomal rpoN gene by the mutant rpoN gene through homologous recombination. Examination of the phenotypes of the P. putida rpoN mutant thus obtained allowed the identification of a series of metabolic functions whose expression depends upon the RpoN sigma factor. The rpoN mutation in P. putida affected the utilization by this organism of nitrate, urea, and uncharged amino acids, namely, alanine, glycine, isoleucine, leucine, and serine, as nitrogen sources. The mutation also affected the utilization of the above-mentioned amino acids, as well as lysine, C4-dicarboxylates (succinate, fumarate), and alpha-ketoglutarate, as carbon sources. In contrast to the P. putida wild-type strain, the rpoN mutant was nonmotile. The colony morphology of the mutant strain was different from that of the wild-type strain. Studies on the expression of the TOL plasmid catabolic operons in the mutant strain demonstrated that transcription from the upper-operon promoter and from the xylS gene promoter requires the RpoN sigma factor.

Amino Acids↗
PubMed1989

[The number of active sweat glands (PSI, palmar sweat index) as a psychophysiologic parameter].

Two laboratory studies were carried out to assess the behavior of the active palmar sweat glands in both an active and a passive coping situation. Stressor in study I was watching a distressing film, in study II mental arithmetic. Subjects were male students, 17 in experiment I, 20 in experiment II. Both experiments involved a 10-minute baseline phase, a 10-minute stress period, and a follow-up of 10 minutes. PSI was assessed at 90-sec intervals and averaged across phases, as were readings in SCL, SCR, heart rate, diastolic and systolic blood pressure. PSI could be determined in 16 subjects of each study. In both experiments PSI increased significantly from baseline to stress (p less than 0.1%) and decreased from stress to follow-up (p less than 0.1%), and thus proved to be the most sensitive indicator for stress. The interrater reliability for counting the number of active sweat glands was high when the area for evaluation was defined unambiguously. Since the assessment of the PSI does not require a sophisticated technology and is thus also applicable in field research, we suggest giving more consideration to this variable.

Adult↗
PubMed1988

[A coupled enzyme system for detection of phospholipase A2 inhibitors].

A coupled assay of phospholipase-A2 and lipoxygenase that especially can be applied to the determination of phospholipase-A2-inhibition is described. A partialsynthetic dilinolenoylglycerophosphocholine is used as substrate in the form of mixed micelles with Twenn-20. Pentadienoic fatty acids primarily produced by venom phospholipase-A2 are peroxydized in a second step quantitatively. Diminution in oxygen content is registrated by an oxygen sensitive electrode and the reaction process is plotted continuously. The usefulness of this assay in the screening of inhibitors and disturbing influences are discussed.

Electrodes↗
PubMed1988

[Azoles. 18. Sulfonylindazole derivatives].

The nucleophilic substitution of hydrogen to synthesize the sulphonyl indazole derivatives 9-16 is described. The structures of the substitution products are discussed using H-NMR spectra. Chemical structural proof was given by steric hindrance observed in the process of chorination of 9-16. The compounds 3, 4, 7, 8, 14, and 16 are studied to find an inhibition on phospholipase-A2 and lipoxygenase-I.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1981

[Studies on the pharmacokinetics of pipemidic acid in renal insufficiency (author's transl)].

After an oral single dose of 400 mg pipemidic acid administered to 7 patients with renal insufficiency of varying degrees of severity, serum concentrations were determined by microbiological and spectrofluorimetric methods. The results obtained revealed maximum values ranging between 1.8 and 7.2 micrograms/ml with a biological half-life of 5.7--16 h. Of some therapeutic significance was an increase in serum concentrations amounting to 2.6--12.8 micrograms/ml when pipemidic acid was administered at normal doses (2 X 400 mg/d) for 3 days. Under maintenance therapy maximum concentrations of microbiologically active substance in urine were found to range between 177 and 580 micrograms/ml. Even in severely impaired kidney function urine concentrations averaged 230 micrograms/ml, which indicates that therapeutically sufficient concentrations can be maintained by regular administration of normal doses at unaltered dosage intervals.

Adult↗
PubMed1978

[Polycythemia vera, clinical aspects and disease course].

The data of 140 patients with polycythemia vera during the period 1955--1975 were analyzed with regard to clinical signs and prognosis. The average age was 53,4 years. The sex ratio was 1.9:1 in favor of men. The most frequent symptoms were headache and vertigo. In more than half of the cases hepatosplenomegaly and hypertension were found. Besides typical changes in the blood count with elevated erythrocytes, hemoglobin, hematocrit, leukocytes and thrombocytes, increased levels of alkaline leukocyte phosphatase and uric acid were found. As to therapy, after 32P-medication the survival was two years longer than after phlebotomy. In 9 patients osteomyelofibrosis developed, and in 7 cases chronic myeloic leukemia. The mean age of death was 61 years.

Adolescent↗